1. Field of the Invention
The present invention relates to a reflector used in a reflective liquid crystal display device or the like, a reflective liquid crystal display device using such a reflector and a method for fabricating such a reflective liquid crystal display device.
2. Description of the Related Art
The most important characteristic for a reflective liquid crystal display device is the brightness of a display. Therefore, regardless of the display modes, it is important to design a reflector which efficiently reflects ambient light and to develop a method for fabricating such a reflector with high repeatability.
Japanese Laid-Open Patent Publication No. 4-243226 discloses a method for fabricating a reflector having concave/convex portions of a photoresist. According to the method, cylindrical portions are formed on a substrate by developing a photoresist thereon. Then, the cylindrical portions on the substrate are heated to be melted and deformed, thereby forming the concave/convex portions which provide the resultant reflector with a capability of diffusing light incident thereon. This method will be described in detail in the Comparative Example below.
A display such as a display panel of a portable communication apparatus is likely to be viewed from a direction which is normal to the display panel. In such a case, light diffused in other directions (e.g, light reflected in a horizontally inclined direction) is wasted.
According to the above method disclosed in Japanese Laid-Open Publication No. 4-243226, the concave/convex portions are formed by "isotropically" deforming the cylindrical portions on the substrate. Therefore, each of the resultant concave/convex portions has a circular shape as viewed from above, and is concentric with the original cylindrical portion. Due to such a configuration of the concave/convex portions, the intensity distribution of the reflected light is symmetric about an axis normal to the substrate. When such a reflector is used in a reflective liquid crystal display device, light is reflected/diffused in all directions including directions irrelevant to the viewing angle of a user. In other words, such a reflective liquid crystal display device cannot sufficiently utilize light incident thereupon.
In many cases, a reflective liquid crystal display device is used as a display portion of a portable communication apparatus. In many of such cases, an "input pen" (a pen-type input device for inputting data to a pen-based input system) is employed as a means for inputting data. When a user inputs data via the input pen, the display screen is pressed down with the pressure applied thereto by the user via the input pen. The liquid crystal layer in the display panel is thus partially flattened out, thereby causing a disturbance in images on the display. In order to solve such a problem, it is effective to provide a polymer matrix in the liquid crystal layer between a pair of substrates so as to support the liquid crystal cell. However, it is difficult to arrange the polymer matrix into a desired pattern, and portions of the polymer matrix may therefore be undesirably located within a pixel region, thereby weakening the contrast of the display.